9702 · 19.2
Energy stored in a capacitor
Capacitors are like tiny rechargeable batteries, storing electrical energy in an electric field. The more charge and voltage, the more energy they hold, released gradually when discharged.
Need to know
What you need to know
- 19.2 Energy stored in a capacitor.
- The charge (Q) on a capacitor is directly proportional to its potential difference (V).
- The area under the curve of a potential-charge graph is equal to the area under a triangle .
- This area is the energy stored in a capacitor.
- The energy stored (W) is therefore W =1/2 QV Substituting Q = CV we get W = ½ CV 2.
Explanation
Capacitor Energy: The Basics
- **Charge Up:** A capacitor collects charge on its plates, building up a potential difference.
- **Store Energy:** This charge separation creates an electric field, storing electrical potential energy.
- **Calculate Power:** Energy stored is proportional to charge and voltage, representable by the area under a Q-V graph.
- **Discharge:** When connected to a circuit, the stored energy is released as current, decaying exponentially.